Several prior U.S. Patents, namely U.S. Pat. Nos. 1,621,508; 3,466,802; 3,466,803; 4,069,617; and 4,114,945, have been devoted to the provision of slides or guide rollers for supporting vertically movable windows in window guideway channels. In automotive applications there has been a continuing problem of preventing window slides from rattling in the guide channels. In U.S. Pat. No. 3,466,803 provision is made for preventing rattling of the window sliders in one lateral direction in the guide channel. In U.S. Pat. No. 3,466,802 provision is made for preventing rattle in two lateral directions in the window guide channel, by biasing portions of the slider laterally against the side walls and the opposed based walls of the guide channel. However, in this prior art the efforts to prevent rattle of the sliders by biasing the slider in two lateral directions has involved either complicated slider mechanisms including several cooperating pieces and spring elements which unacceptably increase the cost of the slider or the slider design has not functioned effectively to prevent rattle.